关于jQuery脚本的简单问题

Question

I have the following think.

When a user types a number bigger than 10 then there is a message appeared. How to remove this message let's say after 2 seconds ?

Also if you type a number let's say 8 and hit the backspace, there is a 0 appeared. How to have number 1 appeared in the textbox from the beginning but also any time that the user hits backstage to delete his choice like my example above? I tried to add value="1" into the textbox but it does not show the result in the div from the beginning.

Thank you for your help

UPDATE I had a small problem with the fiddle, I updated it

Answer 1

已经有一段时间了，但是尝试一下：

$('#message').delay(2000).hide();

Answer 2

You should use:

You can use settimeout for this:

setTimeout(function(){ 
  // remove the message
}, 2000); // time in miliseconds

Also your code does not work and display's NaN when I try to enter something.

Also use:

var code = (e.keyCode ? e.keyCode : e.which);

to find out which key was pressed:

jQuery Event Keypress: Which key was pressed?

EDIT

If you want the value to be displayed at page load add the stuff to an function and call it on document ready:

http://jsfiddle.net/pBeM8/20/

EDIT2

Updated fiddle to also display 1 after using backspace

http://jsfiddle.net/pBeM8/22/

Answer 3

Something like

$('#purchases').keydown(function(e){
   if(!(e.which >= 48 && e.which <=58) && e.which !== 8 && e.which !== 46 && e.which !== 37 && e.which !== 39){
       e.preventDefault();
   }
})
.keyup(function(){
   val = parseInt($(this).val() || 0, 10);
   if(val > 10){
       val = 10;
       $(this).val(10);
       $('#message').text("no more than 10");
       setTimeout(function() { $('#message').text(""); }, 2000);           
   }
   $('#amount').text(val * 10);
});

See a Demo

EDIT:

In line with youer comment, here's a revised version

var purchases = $('#purchases'),
    amount = $('#amount'),
    message = $('#message');

purchases.keydown(function(e) {
    if (!(e.which >= 48 && e.which <= 58) && e.which !== 8 && e.which !== 46 && e.which !== 37 && e.which !== 39) {
        e.preventDefault();
    }
}).keyup(function() {

    var val = purchases.val();

    if (!val) {
        amount.text(1);
        return;
    }

    val = parseInt(val, 10);

    if (val > 10) {
        val = 10;
        $(this).val(10);
        message.text("no more than 10");
        setTimeout(function() {
            message.text("");
        }, 2000);

    }

    amount.text(val * 10);
}).val(1);

New Demo

Answer 4

This would work:

$('#purchases').val(1).keyup()

after you add your handlers: http://jsfiddle.net/pBeM8/16/

Answer 5

It looks like you could benefit from running parseInt() on the input that you read in.

Alternatively, you can go for the cool HTML5 solution by adding a pattern attribute to your input element, assuming your input is wrapped in a form and submitted:

<form>
    <input type="text" pattern="^\d$" />
</form>

Should allow only one numeric character as input.